The Jewels of Medina Were The Jews of Medina

Here's the NYTimes' review of the new book, "The Jewel of Medina".

Actually, the real "jewels" of Medina were its Jews:

Muhammad arrived in Medina in 622 believing the Jewish tribes would welcome him. Contrary to expectation, his relations with several of the Jewish tribes in Medina were uneasy almost from the start...Certain individual pagans and recent Medinan converts to Islam tried to thwart the new arrangement in various ways, and some of the Jewish clans were uneasy with the threatened demise of the old alliances. At least three times in five years, Jewish leaders, uncomfortable with the changing political situation in Medina, went against Muhammad, hoping to restore the tense, sometimes bloody-but predictable-balance of power among the tribes.

According to most sources, individuals from among these clans plotted to take his life at least twice, and once they came within a bite of poisoning him. Two of the tribes--the Banu Nadir and the Banu Qaynuqa--were eventually exiled for falling short on their agreed upon commitments and for the consequent danger they posed to the nascent Muslim community...

...As a siege began, the Banu Qurayza nervously awaited further developments. Learning of their intention to defect and realizing the grave danger this posed, Muhammad initiated diplomatic efforts to keep the Banu Qurayza on his side. Little progress was made. In the third week of the siege, the Banu Qurayza signaled their readiness to act against Muhammad, although they demanded that the Meccans provide them with hostages first, to ensure that they wouldn't be abandoned to face Muhammad alone. Yet that is exactly what happened. The Meccans, nearing exhaustion themselves, refused to give the Banu Qurayza any hostages. Not long after, cold, heavy rains set in, and the Meccans gave up the fight and marched home, to the horror and dismay of the Banu Qurayza.

The Muslims now commenced a 25-day siege against the Banu Qurazya's fortress. Finally, both sides agreed to arbitration. A former ally of the Banu Qurayza, an Arab chief named Sa'd ibn Muadh, now a Muslim, was chosen as judge. Sa'd, one of the few casualties of battle, would soon die of his wounds. If the earlier tribal relations had been in force, he would have certainly spared the Banu Qurayza. His fellow chiefs urged him to pardon these former allies, but he refused. In his view, the Banu Qurayza had attacked the new social order and failed to honor their agreement to protect the town. He ruled that all the men should be killed. Muhammad accepted his judgment, and the next day, according to Muslim sources, 700 men of the Banu Qurayza were executed. Although Sa'd judged according to his own views, his ruling coincides with Deuteronomy 20:12-14.

Most scholars of this episode agree that neither party acted outside the bounds of normal relations in 7th century Arabia.

and here:

Many Medinans converted to the faith of the Meccan immigrants both before and after Muhammad's emigration, but only a few came from Jewish backgrounds because most of the Jewish community rejected Muhammad's status as a prophet. Their opposition "may well have been for political as well as religious reasons". According to Watt, "Jews would normally be unwilling to admit that a non-Jew could be a prophet."...In the Constitution of Medina, Jews were given equality to Muslims in exchange for political loyalty. However, after each major battle with the Medinans, there were accusations of Jewish tribal treachery for aiding the enemies of the community in violation of the Constitution of Medina. After Badr and Uhud, the Banu Qainuqa and Banu Nadir, respectively, were expelled "with their families and possessions" from Medina.